Brouillet Audrey, Sultan Benjamin
ESPACE-DEV, Univ Montpellier, IRD, Univ Guyane, Univ Reunion, Univ Antilles, Univ Avignon, Maison de la Télédétection, Montpellier, Cedex, France.
PLoS One. 2025 Jun 17;20(6):e0293551. doi: 10.1371/journal.pone.0293551. eCollection 2025.
Consequently to global warming, multi-sectoral impacts are observed and should intensify in the future, affecting sectors of water resources, agriculture, weather extremes and health. Related projected change signs, their possible emergences from the historical variability, and how these emergences may cumulate in time and space could thus result in severe risks or benefits for local populations. Using the world's largest cross-sectoral climate-related impact multi-model simulations database Inter-Sectoral Impacts Model Intercomparison Project (ISIMIP), here we quantify for the first time the Time of Emergence (TOE) of historical and future simulated changes in multiple climate-related indicators at a global scale. We assess how both adverse changes (i.e. stressors) and beneficial changes (i.e. benefits) could cumulate during the century. Based on ISIMIP2b (ISIMIP phase 2b) and a low mitigation future scenario (RCP6.0), we find that many land areas are characterized by a multi-model TOE earlier than 2020 for the majority of the 10 analyzed multi-sectoral indicators. This illustrates an already reached new equilibrium-state resulting from global warming for many sectors including hydrology, agriculture and weather extremes. However, the TOE varies depending on the region and the sectoral indicator, encompassing both projected stressors and beneficial changes. The largest number of cumulated emergences of cross-sectoral stressors is projected in the tropics and include detected TOE for higher heat stress extremes, and declining crop yields. Conversely, northern mid- and high- latitudes experience the greatest number of cumulated emergences of beneficial changes, primarly associated with future crop yields increase. These cumulative emergences of stressors (in the tropics) and beneficial changes (in northern latitudes) reach their peak before 2050, indicating an early impact and related emergence on multiple sectors. Nevertheless, substantial uncertainties are exhibited in this multi-model assessment of TOE, particularly in the tropics due to a cascade of uncertainties combining climate models, impacts models, aggregated cross-sectoral impacts, and TOE detection. This study brings time constrains of multiple climate-related changes. It particularly highlights the heightened and early cumulated stressors projected in tropical regions that may further exacerbate disparities and inequalities with northern latitudes. These results also confirm the tropics paradox where fewer greenhouse gas emissions correspond to more adverse impacts from global warming. Without further mitigation and adaptation strategies, vulnerable socio-economic conditions and limited resources in these areas will amplify the negative consequences arising from early and cumulative cross-sectoral emergences, both for populations and ecosystems.
由于全球变暖，已观察到多部门影响，且未来这种影响会加剧，涉及水资源、农业、极端天气和健康等领域。相关的预测变化迹象、其可能从历史变率中出现的情况，以及这些出现情况如何在时间和空间上累积，可能会给当地居民带来严重风险或益处。利用世界上最大的跨部门气候相关影响多模型模拟数据库——跨部门影响模型比对计划（ISIMIP），我们首次在全球尺度上量化了多个气候相关指标的历史和未来模拟变化的出现时间（TOE）。我们评估了不利变化（即压力源）和有益变化（即益处）在本世纪内如何累积。基于ISIMIP2b（ISIMIP第二阶段b）和低减排未来情景（代表性浓度路径6.0），我们发现，对于所分析的10个多部门指标中的大多数而言，许多陆地区域的多模型TOE早于2020年。这表明包括水文、农业和极端天气在内的许多部门已经因全球变暖而达到了一个新的平衡状态。然而，TOE因地区和部门指标而异，包括预测的压力源和有益变化。预计热带地区跨部门压力源的累积出现次数最多，包括检测到的更高极端热应激和作物产量下降的TOE。相反，北半球中高纬度地区有益变化的累积出现次数最多，主要与未来作物产量增加有关。这些压力源（在热带地区）和有益变化（在北半球）的累积出现在2050年前达到峰值，表明对多个部门有早期影响和相关出现情况。尽管如此，在对TOE的这种多模型评估中仍存在大量不确定性，特别是在热带地区，因为气候模型、影响模型、综合跨部门影响和TOE检测等一系列不确定性相互交织。本研究给出了多个气候相关变化的时间限制。它特别强调了热带地区预计会出现加剧且早期累积的压力源，这可能会进一步加剧与北半球的差距和不平等。这些结果也证实了热带地区的悖论，即温室气体排放量较少却对应着全球变暖带来的更多不利影响。如果没有进一步的减排和适应策略，这些地区脆弱的社会经济状况和有限的资源将放大早期和累积的跨部门出现情况所带来的负面后果，无论是对人口还是对生态系统。
